1. Field of the Invention
The present invention particularly relates to a structure of a partition side member of a notchback type vehicle.
2. Description of Related Art
In a vehicle, a partition panel is provided at a rear part of a vehicle body in order to partition the vehicle body into a vehicle interior and a luggage compartment (a luggage space or a trunk space). This partition panel is located at a vertically middle position in the rear part of the vehicle body and has a function of a component that contributes to the vehicle body rigidity, that is, torsional rigidity, in particular, of the rear part. In other words, an improvement in rigidity of the partition panel enables improvement in driving stability of the vehicle and noise reduction in the vehicle interior. For this reason, there is a demand for a partition panel having higher rigidity in itself, and also having higher joint rigidity at vehicle-body side quarter panels and the like joined to both the right and left sides of the partition panel.
Moreover, it is important to secure the joint rigidity of both the right and left ends of the partition panel and side panels. This is because the partition panel has an effect of preventing deformation of the side panels when attachment bolts for attaching seat belt guides are pulled obliquely, i.e., forwardly and downward of the vehicle body with loads applied by seat belts for restraining the bodies of passengers. By securing this joint rigidity, it is possible to mitigate local deformation of the vehicle body and to disperse the loads to peripheral panels.
Accordingly, among conventional vehicle body structures, there is a structure, as disclosed in JP 2009-101975 A, in which partition side panels separated from a partition panel are joined to both the right and left end sides of the partition panel to achieve improvement in rigidity on both the right and left sides of the partition panel while avoiding an increase in weight. Moreover, in order to achieve further improvement in rigidity, this vehicle body structure employs a structure in which a partition reinforcement is attached to backsides (vehicle rear side) of the partition side panels to form closed cross sections at both end sides of the partition reinforcement when viewed in a vehicle width direction and in a vehicle vertical direction.
In addition, JP 2006-256351 A discloses a structure in which a partition side panel is divided into an upright wall portion located on a vehicle front side thereof and a horizontal portion located on a vehicle rear side thereof, and a reinforcement member is provided between the upright wall portion and a partition panel. In this way, it is possible to improve the rigidity on both the right and left sides of the partition panel and to improve the joint rigidity of the upright wall portion and a closed cross section portion provided on the front side of the partition panel.
Furthermore, JP 8-276865 A discloses a structure in which the rigidity is improved in such a way that a closed cross section is formed by installing a panel having a “dogleg” cross-section shape to the vehicle front side of a partition side panel.
However, the conventional vehicle body structures as described above cannot achieve improvement in the rigidity of the closed cross section unless the panels that form the closed cross section are firmly joined together. For this reason, in the above-described conventional vehicle body structures, the panels for forming the closed cross section need to be joined together by spot welding with no intervals, or by other similar processing.
Nevertheless, a notchback type vehicle which has a trunk compartment at a rear part of the vehicle generally employs a structure in which a door of the trunk compartment is opened and closed by a rotation operation using hinges, and trunk hinge brackets thereof are attached to both the right and left sides of a partition panel (or to partition side panels in a case in which the partition side panels are provided). A layout of an arm of such a hinge affects a rotation trajectory of opening and closing operations of the trunk door. The layout can be set easily when attachment positions of the trunk hinge brackets and the relative position of the trunk door are appropriate. However, if these positions are not appropriate, the rotation trajectory of the trunk door has a problem, and therefore a complicated link mechanism needs to be employed as a countermeasure. For this reason, certain distances need to be provided between the attachment positions of the trunk hinge brackets and the relative position of the trunk door, and it is important to secure design flexibility for the attachment positions of the hinges. In addition, the trunk hinge brackets receive loads in the opening and closing operations of the trunk door and loads of supports (springs) for opening the trunk door. Therefore, the trunk hinge brackets are required to secure the sufficient attachment rigidity.
For example, in a structure of a closed cross section of a conventional partition reinforcement as shown in FIG. 7, a joining point of a partition side panel 51 and a partition reinforcement 52 is thickly provided. Accordingly, a trunk hinge bracket 53 needs to be provided in a position avoiding the joining point. In this case, the trunk hinge bracket 53 needs to be provided behind a joining flange 52a of the partition reinforcement 52 in the vehicle front-rear direction. Therefore, a distance a between the attachment position of the trunk hinge bracket 53 and a trunk door (not shown) tends to become shorter. Therefore, the trunk hinge brackets may not achieve sufficient attachment rigidity.